> <i>const performs a lot better in optimized code than var or let</i><p>This puzzles me; if only ever one value is assigned, I would have expected at least <i>let</i> to perform identically to <i>const</i> in optimised code, because I expect the optimiser to look at the <i>let</i> and say “never reassigned, turn it into a <i>const</i>”. By the sound of it, I’m wrong, and I’d be interested to know <i>why</i> I’m wrong.